Semiconductor optoelectronic devices, such as lasers, can be used for free space communications and other applications by modulating an optical output (e.g., laser beam) at the transmitter and detecting the modulation at the receiver. Such optoelectronic devices include vertical-cavity surface-emitting lasers (VCSELs), which are particularly well suited for free space communications and other applications. VCSELs are well suited for free space communications and other applications because the entire laser can be switched on and off very rapidly, without the need for an external optical shutter, simply by modulating the bias power to the VCSEL. However, individual VCSELs have a limited range over which they can be used to communicate, since one high speed VCSEL by itself is typically not able to produce more than a few milliwatts of optical power. One way to overcome the limited range of individual VCSELs is to use an array of VCSELs when communicating over longer distances. To effectively communicate with an array of VCSELs, all of the individual VCSELs of the array should be operated at full power and with coherent phase. In order to make all of the lasers in a VCSEL array operate coherently and at full power, a phase-balanced, impedance-matched driver may be needed to drive each individual VCSEL of the VCSEL array.